code: def test_mean(self):
      np.testing.assert_equal(self.link.mean, self.link.base.mean)
  
file_path: chainercv/tests/links_tests/model_tests/fpn_tests/test_fpn.py
imports: from __future__ import division
  import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links.model.fpn import FPN
label_desc: Use image node_id 2 for calling the TestFPN obj's underlying member method code with example usage: obj.test_mean() without return types